1. Field of the Invention
The present invention concerns a switchable hydraulically damping mount. The hydraulically damping mount includes a supporting mount and a supported mount which are resiliently braced against one another by a support spring made of an elastomeric material. The support spring includes at least two working chambers, filled with fluid and arranged one behind another in the direction of the vibrations introduced during operation. The chambers are delimited on the sides facing one another by a common partition and are connected in a fluid-conveying manner to one another by at least one damping channel arranged in the partition. The partition has a central recess that is a component of a passthrough opening, such that the passthrough opening can be opened by an actuator of a positioning device, which can be acted on by a pressure medium.
2. Description of the Prior Art
A mount of this kind is shown in DE-OS 41 41 332. The actuator in the mount shown in that publication consists of a piston that is associated, in a gas-tight manner allowing relative movement, with a control pressure capsule. The control pressure capsule can be acted upon by a pressure medium and is arranged in fixed fashion in the mount housing, such that the control pressure capsule can be acted upon pneumatically by negative or positive pressure depending on the configuration of the mount. This mount is configured as an engine mount, the central passthrough opening being closed off during operation by a plug-shaped bead. Low-frequency vibrations with large amplitudes are damped by a displacement of fluid inside the damping channel, while high-frequency vibrations with small amplitudes are isolated by the axially movable membrane arranged inside the partition. However, in the device disclosed in DE-OS 41 41 332, the annular surface of the membrane has small dimensions. In addition, the fluid volume inside the open passthrough opening used to achieve the vibration canceling effect is comparatively small.